The Total Eclipse of the Sun, April 16, 1893. 17 



in all probability, due to the haze, or opalescence, in the air which 

 prevailed at the time. This haze, caused more by suspended and 

 finely divided solid matter than by precipitated moisture, undoubtedly 

 contributed to the general sky-illumination at the time of totality. 

 The actual gloom during this phase of the eclipse at Fundium was 

 certainly much less than at Grenada in 1886. It must not be for- 

 gotten, however, that the altitude of the sun was very different on 

 the two occasions. At Grenada it was only about 19 : the amount 

 of cloud was from seven to eight (overcast = 10) at the time of to- 

 tality, and much of the cloud was in the neighbourhood of the sun : 

 whereas at Fundium the sun's altitude was t52, and the sky was of 

 a bluish- grey colour and practically free from cloud. 



The effect of these different conditions in the sky in the neighbour- 

 hood of the disc is seen in Mr. Forbes' measurements when com- 

 pared with those of Lieutenant Douglas, at Grenada. The ten fairly 

 concordant observations at Fundium give, as already stated, an 

 average value of 0*026 Siemens units at 1 ft. from the screen; and 

 the value observed by Lieutenant Douglas, 15 seconds after totality, 

 with the same photometer, although with a different lamp and galva- 

 nometer, was 0'0197 light units. 



" The Total Eclipse of the Sun, April 16, 1893. Report and 

 Discussion of the Observations relating to Solar Physics." 

 By J. NORMAN LOCKYER, C.B., F.R.S. Received April 17, 

 Read April 30, 1896. 



(Abstract.) 



The memoir first gives reports by Mr. Fowler and Mr. Shackleton 

 fis to the circumstances under which photographs of the spectra of 

 the eclipsed sun were taken with prismatic cameras in West Africa 

 and Brazil respectively on April 16, 1893. These are followed by a 

 detailed description of the phenomena recorded, and a discussion of 

 the method employed in dealing with the photographs. The coronal 

 spectrum and the question of its possible variation, and the wave- 

 lengths of the lines recorded in the spectra of the chromosphere and 

 prominences, are next studied. 



Finally, the loci of absorption in the sun's atmosphere are con- 

 sidered. 



The inquiry into the chemical origins of the chromospheric and 

 prominence lines is reserved for a subsequent memoir. 



The general conclusions which have been arrived at are as 

 follows : 



(1) With the prismatic camera, photographs may be obtained with 



VOL. LX. 



